U.S. Pat. No. 4,001,742 entitled "Circuit Breaker Having Improved Operating Mechanism" describes a circuit breaker capable of interrupting several thousand amperes of circuit current at several hundred volts potential. As described therein, the operating mechanism is in the form of a pair of powerful operating springs that are restrained from separating the circuit breaker contacts by means of a latching system. Once the operating mechanism has responded to separate the contacts, the operating springs must be recharged to supply sufficient motive force to the movable contact arms that carry the contacts.
U.S. Pat. No. 4,672,501 entitled "Circuit Breaker and Protective Relay Unit" describes the use of a digital circuit interrupter employing a microprocessor in combination with ROM and RAM memory elements to provide both relaying as well as protection function to an electrical distribution system.
This circuit breaker and protective relay unit can be used on various ampere-rated circuit breakers depending on the operator's requirements. This invention provides a trip unit rejection scheme whereby only the correct trip unit is installable within the corresponding circuit breaker assembly.
U.S. Pat. No. 4,870,531 entitled "Circuit Breaker with Removable Display and Keypad" describes a digital display and keypad used to select circuit breaker trip settings and allows the settings to be viewed.
This invention allows use of the display and keypad assembly remote from the circuit breaker to display the circuit breaker trip settings as well as cause-of-trip information.
U.S. patent application Ser. No. 08/239,822 entitled "Digital Circuit Interrupter with Multiple Accessory Function" describes an integrated circuit breaker having several accessory functions along with automatic overcurrent protection, which allows selection between the various accessory functions in different combinations. Separate switches are arranged on the circuit breaker to allow factory as well as field selection of the accessory function combinations.
When such switches are set by the operator within an electrical distribution system, it is important that the switches not be changed so that selected accessories such as a bell alarm remain operational at all times.
U.S. patent application Ser. No. 08/200,048 filed Feb. 22, 1994 entitled "Digital Circuit Interrupter with Battery Back-up Facility" describes a digital circuit interrupter utilizing current transformers for operating power that includes a battery to power-up the trip unit as well as to power the display after an overcurrent trip occurrence to enable an operator to determine both the magnitude as well as the cause of the overcurrent condition.
One purpose of this invention is to provide access means to the batteries used within the battery recess in the trip unit cover to allow for test and replacement.